問46
頻出度★★★
過去の類似プロジェクトのコスト実績を用いて, 新たに開始するプロジェクトのコストを類推し見積もった。このようなコスト見積り方法の特徴はどれか。
平成28年度 春期 ITパスポート試験 問46
マネジメント系システム開発技術 › システム開発技術
This question's explanation and your answers so far.
解説
問 46
Incorrectア
A method that builds up from detailed information (bottom-up estimation) breaks the work into fine parts and sums them up, so it has a large work effort. Analogy-based estimation makes a rough estimate from past results, so its work effort is actually small; the statement is reversed.
Incorrectイ
Analogy-based estimation is suited to rough estimation in the early stage, when detailed information is not yet available. In the later stage, once the work content becomes concrete, one shifts to higher-accuracy methods such as bottom-up build-up, so it is wrong to say it is often used in the later stages.
Incorrectウ
Analogy-based estimation is only a rough estimate and is less accurate than other detailed estimation methods. That more accurate results can be expected is the exact opposite of its characteristic, so it is wrong.
- エ
正解 The estimation method in this question is analogy-based estimation, which roughly infers the cost of a new project from the actual cost results of past similar projects. Because it reuses past results, it takes little effort and cost to estimate and can be done in a short time; however, because it does not individually examine differences in scale or conditions, its accuracy is low. Therefore, choice エ, which states that it requires less cost to estimate than other methods but is inferior in accuracy, is the correct characteristic.
ここがポイント
- Analogy-based estimation is a top-down method that roughly estimates the cost of a new project from the actual results of past similar projects. It takes little effort and cost and suits the early stage, but its accuracy is low.
- In contrast, bottom-up estimation sums up the details, so it is highly accurate but has a large work effort and cost — grasp this trade-off.
用語